This undated photo provided by the Wisconsin Historical Society shows 1st Lt. Alonzo Cushing. A Civil War soldier is to be honored with the nation's highest military decoration 151 years after his death.

More than 150 years after the Battle of Gettysburg, a Civil War hero is finally getting his due.

The White House announced Tuesday that 1st Lt. Alonzo Cushing will be awarded the Medal of Honor in a special ceremony on Sept. 15 for his “gallantry above and beyond the call of duty” during that battle.

At 22 years old, Cushing, a West Point graduate, commanded 110 men and six cannons, and his men stood their ground under severe artillery bombardment for three days. On the final, fateful day of the battle, 13,000 Confederate infantrymen involved in Pickett’s Charge threatened to overtake the Union soldier's position.

“Refusing to evacuate to the rear despite his severe wounds, he directed the operation of his lone field piece continuing to fire in the face of the enemy,” reads a statement from the White House. “His actions made it possible for the Union Army to successfully repulse the Confederate assault.”

On July 3, 1863, the final day of the battle, as the Confederate forces finally began to fall back, Cushing received a final, fatal wound to the head. A stone marker dedicated to Cushing marks the site where he fell. He was buried at West Point with honors, but until now had been overlooked for the nation’s highest military award.

Typically, the Medal of Honor is supposed to be awarded within three years of the act of heroism, but Congress can make exceptions for historic acts of bravery. Cushing received such a congressional exemption this past December along with two Vietnam veterans, Army Command Sgt. Maj. Bennie Adkins and Army Spc. 4 Donald Sloat, who will also receive their medals during the Sept. 15 ceremony.

Cushing’s family and Civil War buffs had lobbied for him to receive the award since the 1980s. Margaret Zerwekh, a Delafield, Wis., woman and granddaughter of another Union veteran of the Civil War, led that charge. For decades, she petitioned congressmen, senators, and presidents to recognize Cushing’s valiant efforts, according to The New York Times. She mostly received form letter responses until the early 2000s, when Sen. Russ Feingold (D) of Wisconsin took up her cause.

In February 2010, Army Secretary John McHugh recommended that he be considered for the medal, but Congress failed to include the necessary exemption from the Defense bill that year.

In March, President Obama awarded the medal to 24 Army veterans who served in World War II, Korea, or Vietnam and were overlooked because of discrimination.